Note: Descriptions are shown in the official language in which they were submitted.
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AN ADSORBENT
TECHNICAL FIELD
[0001] The
present invention generally relates to adsorbents for the removal of
perfluoroalkyl and polyfluoroalkyl substances from water.
BACKGROUND
[0002]
Perfluoroalkyl and polyfluoroalkyl substances (PFASs) have been widely
used for various purposes, including for fire-fighting foams. Aqueous film-
forming foams
(AFFFa) containing PFASs have been demonstrated to be highly effective in
fighting
hydrocarbon fuel fires and as such, significant numbers of fire-fighting
training facilities
around the world have been identified as being contaminated by PFAS.
[0003] The
entire family of PFASs may be broken down into four sub-classes,
namely perfluoroalkyl sulfonic acids (PFSAs), perfluoalkyl carboxylic acids
(PFCAs),
perfluoroalkyl sulfonamides (FOSAs) and fluorotelomer sulfonic acids (FTSs).
[0004]
PFASs are considered almost non-degradable in nature and therefore pose a
significant challenge for remediation, with many conventional approaches to
treatment of
PFAS in water not being effective. The complex chemistry of PFAS make them
highly
soluble and therefore easily transported by groundwater and surface water. As
the
chemistry of PFAS substances changes with increasing carbon chain length, pH,
salinity
and other variables, PFAS contamination is considered extremely difficult and
expensive
to remediate. Furthermore, there currently exists no single method that that
can adequate
remediate contamination of the entire family of PFAS chemicals.
[0005]
Removal of remediation of ground and surface water contaminated with
PFASs typically involves an adsorption process, as PFASs are not effectively
degraded
using biological or chemical treatment options. Granulated activated carbon
(GAC) has
been shown to be an effective substrate adsorbent for long-chain PFASs.
However, GAC
is less effective for the treatment of more hydrophilic shorter chain PFASs,
for example
PFBS (butanoates; C4 lengths). Accordingly, use of GAC filters may be used in
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conjunction with other treatment methods such as reverse osmosis resin to
broaden the
number of PFASs removed during treatment. Combining GAC adsorption with
reverse
osmosis resin adds significantly to the complexity and costs of PFAS
remediation.
Additionally, such a process generates by-products of PFAS contaminated GAC,
and
PFAS contaminated hyper-saline liquor created during RO resin regeneration.
[0006] The reference in this specification to any prior publication (or
information
derived from it), or to any matter which is known, is not, and should not be
taken as, an
acknowledgement or admission or any form of suggestion that prior publication
(or
information derived from it) or known matter forms part of the common general
knowledge in the field of endeavour to which this specification relates.
BRIEF SUMMARY
[0007] The present invention seeks to provide an invention with improved
features
and properties.
[0008] According to one example aspect the present invention provides an
adsorbent for perfluoroalkyl and polyfluoroalkyl substances, wherein the
adsorbent
comprises one or more plant proteins.
[0009] In an embodiment, the one or more proteins include albumins.
[00010] In an embodiment, the one or more proteins include globulins.
[00011] In an embodiment, the one or more proteins include edestin.
[00012] In an embodiment, the one or more proteins include glycinin.
[00013] In an embodiment, the one or more proteins include beta-
conglycinin.
[00014] In an embodiment, the one or more proteins are structurally
similar to
albumins and/or globulins and/or edestin and/or glycinin and/or beta-
conglycinin.
[00015] In an embodiment, the one or more proteins are derived from hemp
seeds.
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1000161 In an embodiment, the adsorbent comprises hemp seeds.
[00017] In an embodiment, the adsorbent comprises hemp protein
isolate.
[00018] In an embodiment, the adsorbent comprises soy protein.
[00019] In an embodiment, the adsorbent further comprises
calcite.
[00020] In an embodiment, the adsorbent further comprises an
inert
substance configured to increase the permeability of the adsorbent.
[00021] In an embodiment, the inert substance is glass beads.
[00022] In an embodiment, the inert substance is gravel.
[00023] According to one example aspect the present invention provides
use of an
adsorbent according to any one of the above aspects or embodiments for
treatment of a
material contaminated with perfluoroalkyl and polyfluoroalkyl substances.
[00024] In an embodiment, the material is groundwater.
[00025] In an embodiment, the material is residual water from soil
washing.
[00026] According to one example aspect the present invention provides a
process
for the treatment of ground water contaminated with perfluoroalkyl and
polyfluoroalkyl
substances, wherein the contaminated ground water is pumped to the surface and
directed
to an adsorption step comprising the adsorbent according to any one of the
above aspects
or embodiments.
[00027] According to one example aspect the present invention provides a
process
for the treatment of ground water contaminated with perfluoroalkyl and
polyfluoroalkyl
substances, wherein a permeable reactive barrier comprising the adsorbent
according to
any one of the above aspects or embodiments is located in the path of an
aquifer
contaminated with perfluoroalkyl and polyfluoroalkyl substances.
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1000281 According to one example aspect the present invention provides a
process
for the treatment of spent adsorbent according to any one of the preceding
aspects or
embodiments, comprising thermal destruction of spent adsorbent.
[00029] In an embodiment the thermal destructions occurs at a temperature
selected
from <700 C, <650 C, <600 C, <550 C, <500 C or <450 C.
[00030] In an embodiment the spend adsorbent is dewatered and dried prior
to
thermal destruction.
[00031] In an embodiment gasses evolved by thermal destruction are
scrubbed with
an alkaline solution, wherein the alkaline solution is subsequently reacted
with calcite to
form fluorite.
BRIEF DESCRIPTION OF FIGURES
[00032] Example embodiments should become apparent from the following
description, which is given by way of example only, of at least one preferred
but non-
limiting embodiment, described in connection with the accompanying figures.
[00033] Figure 1 illustrates PFAS removal from an example high ionic
strength
solution in terms of % removal of total sum of PFAS compounds and sum
PFHxS+PFOS;
[00034] Figure 2 illustrates PFAS removal from an example high ionic
strength
solution in terms of % removal of individual PFCAs;
[00035] Figure 3 illustrates PFAS removal from an example high ionic
strength
solution in terms of % removal of individual PFSAs;
[00036] Figure 4 illustrates PFAS removal from an example low ionic
strength
solution in terms of % removal of total sum of PFAS compounds and sum PFHxS
and
PFOS;
[00037] Figure 5 illustrates PFAS removal from an example low ionic
strength
solution in terms of % removal of individual PFCAs;
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1000381
Figure 6 illustrates PFAS removal from an example low ionic strength
solution in terms of % removal of individual PFSAs;
[00039]
Figure 7 illustrates % removal of total sum of PFAS compounds and sum
PFHxS and PFOS for hemp seed powder and hemp seed in an example low ionic
strength
solution;
[00040]
Figure 8 illustrates % removal of total sum of PFAS compounds and sum
PFHxS and PFOS for hemp seed powder and hemp seed in an example high ionic
strength
solution;
[00041]
Figure 9 illustrates % removal of total sum of PFAS compounds and sum of
PFHxS + PFOS as a function of solid to liquid ratio in an example solution;
[00042]
Figure 10 shows an overlay of three thermogravimetric analysis (TGA) test;
the top series showing mass-loss reactions as a function of time; the middle
series showing
heat flow of the reactions; and the bottom series showing mass-loss as a
function of
temperature;
[00043]
Figure 11 illustrates % removal of total sum PFAS compounds and
sum of PFHxS and PFOS compounds from low ionic strength solutions for HSP and
SPI;
[00044]
Figure 12 illustrates % removal of certain PFCAs compounds for HSP and
HSP and SPI;
[00045]
Figure 13 illustrates % removal of certain PFSAs compounds for HSP and
SPI.
[00046]
Figure 14 illustrates the overall analysis procedure for removal experiments
including the addition of Total Oxidisable Precursor (TOP) analysis.
[00047]
Figure 15 illustrates the removal at low ionic strength of PFOS, PFOA,
/(PFHxS + PFOS), and /PFAS for HSP as a function of solid to liquid ratio.
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1000481 Figure 16 illustrates the removal at high ionic strength of PFOS,
PFOA,
E(PFHxS + PFOS), and EPFAS for HSP as a function of solid to liquid ratio.
[00049] Figure 17 shows the PFAS removal at HSP 10 g/L for a two-stage (A
and
B) removal.
[00050] Figure 18 shows the PFAS removal at HSP 50 g/L for a two-stage (A
and
B) removal.
[00051] Figure 19 shows the PFAS removal at HSP 100 g/L for a two-stage
(A and
B) removal.
[00052] Figure 20 illustrates the removal kinetics of PFCA using HSP A)
at low
(natural) ionic strength with HSP only; B) at low (natural) ionic strength
with HSP and
1.00 g/L calcite (<150 pm); C) at high ionic strength with HSP only; and D) at
high ionic
strength with HSP and 1.00 g/L calcite (<150 m).
[00053] Figure 21 illustrates the removal kinetics of PFSAs using HSP A)
at low
(natural) ionic strength with HSP only; B) at low (natural) ionic strength
with HSP and
1.00 g/L calcite (<150 pm); C) at high ionic strength with HSP only; and D) at
high ionic
strength with HSP and 1.00 g/L calcite (<150 m).
[00054] Figure 22 illustrates the removal of particular PFCAs by HSP, HSP
with
calcite, and activated carbon.
[00055] Figure 23 illustrates the removal of particular PFASs by HSP, HSP
with
calcite, and activated carbon at different ionic strengths.
[00056] Figure 24 illustrates the pseudo-second order (PSO) model for
instantaneous
sorption rate (h) as a function of PFSA carbon chain length.
[00057] Figure 25 illustrates the PFAS removal isotherms for PFOS,
E(PFAS), and
E(PFHxS+PFOS).
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1000581 Figure 26 illustrates modelling of the maximum removal in terms
of mass of
PFAS removed per gram of solid along with the 95% confidence intervals as
derived from
the model fitting process, for A) PFOA, B) PFHxA, C) PFOS, D) PFHxS, E)
E(PFHxS+PFOS), and F) EPFAS.
[00059] Figure 27 illustrates the PFHxS+PFOS sorption isotherm using HSP.
[00060] Figure 28 is a schematic diagram of sequential batch reactors.
[00061] Figure 29 illustrates the thermogravimetric (TG) and heat flow
curves
during combustion of HSP exposed to de-ionised water only.
[00062] Figure 30 illustrates the thermogravimetric (TG) and heat flow
curves
during combustion of HSP exposed to PFOS at an initial concentration of ¨9.6
mg/L/
[00063] Figure 31 illustrates the infra-red difference spectra of HSP
samples
exposed to three different concentrations of PFOS.
[00064] Figure 32 shows the FTIR spectra of the HSP control and HSP
exposed to
PFOS after thermal destruction.
[00065] Figure 33 illustrates the evolved gas analysis during the thermal
destruction
(at 10 C/min) under an oxygen atmosphere for hemp protein powder exposed to
PFOA.
[00066] Figure 34 is a photograph of a laboratory-scale rotary drum
vacuum (RDV)
showing the removal of the spent HSP solid from the treated water stream.
[00067] Figure 35 shows the %PFAS removal for each of a variety of
protein
powders prior to normalization.
[00068] Figure 36 illustrates the Kd values for each plant protein after
normalization
for total protein content. Both the A) linear and B) logarithmic plots are
displayed.
PREFERRED EMBODIMENTS
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1000691 The
following modes, given by way of example only, are described in order
to provide a more precise understanding of the subject matter of a preferred
embodiment or
embodiments.
[00070] In
the Figures, incorporated to illustrate features of an example
embodiment, like reference numerals are used to identify like parts throughout
the Figures.
[00071] It
has been surprisingly found that an adsorbent comprising
proteins may be effective in the removal of aqueous PFASs. In an embodiment,
it has
been surprisingly found that an adsorbent comprising plant proteins may be
effective in the
removal of aqueous PFASs. Example non-limiting plant proteins which may act as
an
adsorbent for PFASs may include: edestin, albumin proteins, globulin proteins
such as
glycinin and beta-glycinin, and/or lupin. In some embodiments, it has been
found that the
inclusion of calcite in an adsorbent comprising a plant protein may enhance
the
effectiveness of the adsorbent. It is to be understood that the invention is
not limited to the
proteins listed above, and may include proteins with similar properties, such
as structural
similarities and/or similar configurations of functional groups and/or amino
acids.
[00072] In
a particular embodiment, it has been surprisingly found that an adsorbent
comprising hemp seed proteins may be effective in the removal of aqueous
PFASs. Hemp
seed protein may be in the form of hemp seeds, crushed hemp seeds, hemp seed
powder
(referred to herein as HSP, hemp seed powder may also be referred to as "Hemp
Powder
Protein" or HPP), hemp protein isolate, mixtures thereof, or any other
suitable form.
Without wishing to be bound by theory, it is thought that the hemp seed
proteins edestin
and/or albumin may be an effective substrate for PFASs remediation by
adsorption.
[00073] It
has been found that use an adsorbent comprising substantially only hemp
seed protein may be remove PFASs from water to below Australian drinking water
standards. For example, use of an adsorbent comprising substantially only hemp
seed
protein may achieve about 98-99% removal of PFSA substances from a low ionic
strength
solution, and may achieve about 96-97% removal of PFSA substances from a high
ionic
strength solution.
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1000741 It
has been found that an adsorbent comprising hemp seed protein and calcite
may be effective in the removal of aqueous PFASs. In some embodiments,
inclusion of
calcite may enhance the effectiveness of an adsorbent in removing certain
PFASs. By way
of example, an adsorbent with approximately equal parts hemp seed protein and
granular
limestone may increase of removal of PFHxA and PFHpA at low and high ionic
strengths.
For example, use of an adsorbent comprising equal parts hemp seed protein and
calcite
may increase removal of PFHxA from about 72% to >99.9% and PFHpA from 78.5% to
>99.9% in low ionic strength solution of about 6mS/cm when compared to use of
hemp
seed protein without calcite. Use of an adsorbent comprising equal parts hemp
seed
protein and calcite in solutions of high ionic strength may increase removal
of PFHxA
from about 42% to about 76% and PFHpA from about 69% to about 84%. Without
wishing to be bound by theory, it is though that an adsorbent comprising hemp
seed
protein and calcite may enhance the adsorption properties for certain species
of PFASs
beyond the mere additive adsorption properties of hemp seed protein and
calcite
considered separately. It is to be understood that an adsorbent comprising
equal parts
protein and calcite is an example embodiment, and adsorbents featuring
different ratios
may be used.
[00075] In
an embodiment, an adsorbent comprising soy protein may be effective in the
removal of aqueous PFASs. Soy protein may be in the form of soy beans, crushed
soy
beans, soy bean meal, soy protein isolate, mixtures thereof or any other
suitable form.
Without wishing to be bound by theory, it is thought that the soy proteins
glycinin and/or
beta-conglycinin may be effective in the removal of aqueous PFASs. Further,
inclusion of
calcite may increase the effectiveness of an adsorbent comprising soy protein.
[00076] In
some embodiments, the adsorbent may comprise one or more proteins
selected from hemp seed protein, soy protein, pea protein, egg protein, whey
protein and
lupin protein.
[00077] In
an embodiment, the adsorbent comprising protein as hereinbefore
described may be used in conjunction with a pump and treat system whereby
groundwater
contaminated with PFASs substances is pumped to the surface for treatment. The
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treatment process may involve an adsorption step where the PFASs contaminated
water is
contacted with the adsorbent as herein described. For example, the adsorbent
may
contained in packed beds through which contaminated groundwater traverses. In
certain
embodiments, the packed bed may include an inert substance to increase the
interstitial
space in the packed bed thereby increasing permeability and flowrate
therethrough in order
to achieve an appropriate residence time. Configuring the permeability of the
packed bed
may also facilitate economic design of the hydraulic circuit used to direct
contaminated
water through the packed bed, for example, by reducing pumping head
requirements. The
inert substance may be glass beads or any other suitable material, and may be
distributed
with the adsorbent in the packed bed. In an embodiment, the adsorbent and
inert substance
may be provided as a pre-mixed product to facilitate easier charging of the
adsorption
apparatus such as a packed bed. Remediated water having undergone the
adsorption step
may then be returned to an aquifer, or discharged to a surface watercourse.
[00078] In an embodiment the adsorbent as herein described may be used to
treat
PFASs contaminated ground water using an in situ permeable reactive barrier
(PRB)
process. Such a process may involve a subsurface wall which may be installed
in a
substantially perpendicular direction to the hydraulic gradient of the PFASs
contaminated
groundwater. As the contaminated ground water passes through the PRB
comprising the
adsorbent, the water may be remediated of PFASs. In certain embodiments, the
adsorbent
in the PRB may be combined with some material to increase permeability
therethrough to
achieve appropriate residence time. Such a material may include gravel, for
example of
size lOmm to 20mm, calcite or any other suitable material.
[00079] In an embodiment the adsorbent as described herein may be used to
treat
residual water generated from washing soils. For example, residual wash water
generated
by washing PFAS contaminated soils may become contaminated with PFAS
compounds,
and thus may be treated using the adsorbents as herein described.
[00080] In an embodiment the adsorbent as described herein may be used to
treat
PFAS contaminated water by way of a series of batch reactors, wherein
contaminated
water passes through each reactor in sequence, and wherein each sequential
reactor
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provides a further amount of adsorbent to further reduce the level of PFASs in
the water.
The effluent of a first reactor in a series becomes the influent of a second
reactor in a
series.
[00081] In an embodiment, once the adsorbent has become spent, it may be
disposed
of by thermal destruction. In some embodiments, the spend adsorbent may first
be
dewatered and dried, for example by air drying, before being thermally
destroyed. It has
been surprisingly found that the spent adsorbent as herein described may be
thermally
destroyed at lower temperatures than may be otherwise anticipated. Without
wishing to be
bound by theory, it is thought that the sorption of PFASs may affect the
bonding strength
of the organic component of the hemp seed protein, thereby enhancing the
thermal
destruction process. In an embodiment, spent adsorbent may undergo thermal
destruction
at a temperature of about <700 C. In an embodiment, spent adsorbent may
undergo
thermal destruction at a temperature of about <650 C. In an embodiment, spent
adsorbent
may undergo thermal destruction at a temperature of about <600 C. In an
embodiment,
spent adsorbent may undergo thermal destruction at a temperature of about <550
C. In an
embodiment, spent adsorbent may undergo thermal destruction at a temperature
of about
<500 C. In an embodiment, spent adsorbent may undergo thermal destruction at a
temperature of about <450 C.
[00082] In an embodiment, gasses evolved by the thermal destruction
process may
be scrubbed, for example using an alkaline solution. The alkaline solution may
then be
reacted to with calcite to form fluorite.
[00083] Many modifications will be apparent to those skilled in the art
without
departing from the scope of the present invention.
EXAMPLE 1
[00084] Two samples (A & B) of approximately 1 litre were obtained from
water
flowing out of the drains under Medowie Road from RAAF Williamtown into Moor's
Creek in NSW, Australia. The samples were placed in a cooler bag with ice
bricks for
transport to the University of Newcastle Geoenvironmental laboratories.
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[00085] Sample A was spiked with analytical grade (Sigma Aldrich)
perfluorooctanoic acid (PFOA) whilst sample B was combined 1:1 with sample A
to form
sample C. Sample C was then split equally to form sample D to which enough KC1
was
added to increase the ionic strength to ¨45 mS/cm. The samples were stored at
4 C.
[00086] A set of batch reactor samples were setup to determine the extent
of PFAS
removal using five different sorbents (51 ¨ S5). Batch tests were done in PFAS
approved
plastic ware, capped and left for at least 3 days in an end-over-end stirrer
to equilibrate.
Blanks were included in each batch test using De-Ionized (DI) water and DI
water made up
to ¨45 mS/cm with KC1. All PFAS analyses were done at ALS laboratories, Sydney
under
the standard suite of 28 analytes as listed in Table 1.
[00087] Laboratory sampling for pH, electrical conductivity (EC), and
major cations
and anions were done on subsamples taken from each batch test. pH electrode
(Orion
9165BN) calibration was completed using pH 4, 7 and 10 NIST buffers until a
slope of 92
- 102% was obtained. EC calibration was done using an Orion Star A322 meter
and a 1413
mS/cm standard as per manual instructions. Anions and cations were analysed
using a
Dionex ICS5000 ion chromatograph running Chromeleon 6.8 software and equipped
with
an A518/AG18 anion analytical/guard columns utilizing 30mM potassium hydroxide
(KOH) eluent. For cations, CS12A/CG12 analytical/guard columns utilizing 20mM
methanesulfonic acid (MSA) eluent. Five point calibration was carried out
prior to analysis
using a Dionex anion combined seven ion standard, and Dionex cation combined
six ion
standard.
[00088] A key parameter in remediation is the amount of sorbent required
to remove
a certain concentration of contaminant. This requires the development of a
sorption
isotherm for each PFAS compound of interest.
[00089] Sorption experiments have been completed for the development of
sorption
isotherms for the PFAS/hemp seed powder system. For these experiments ¨50L of
groundwater was obtained from the most contaminated monitoring well (MW187s)
at
Williamtown RAAF Base, NSW. This groundwater sample has more than 40 times the
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amount of PFHxs+PFOS in experiments using water samples B, C & D (Table 1).
Sorption
isotherms experiments were done via the batch reactor methodology outlined
above.
[00090] Thermogravimetric analysis with differential scanning calorimetry
(TGA-
DSC) was done using a Mettler-Toledo TGA2 instrument running STARe software.
[00091] The PFAS chemistry used in these experiments is shown in Table 1.
The
term PFAS is used to describe all per- or polyfluoroalkyl species, however
this can be
further divided into classes and then individual substances as shown in Table
2.
Taahr 1. Ileinffir P. co:Me.; :ftwral in grtzonthavter ot =iii-giorntown, NSW
tfonvorestt to the AFOA sOked water tomptet cibinine4
/tem 0.4nnes- Eh-nick.. Wstsnwpr end stitagge token frarn Al W18 Kra
ammitati.ng well nen: ine.Watnntown RAM tknm.
Ariaiyte Gitostpkig Anal yte Highest initial initial
initial MW181s
groundwater CIernistry Oiernistry tIletnistry
concenttation Sam* 6 SatrVe C Sample 0
at Witliaristown fspiked with
f..-T....M PFOM
Pertboroal kane PFOS 5.8.2 2.54 2.83 /.6.5 130.0
Sulfouates PR-ix,9 15,6 LOS 6.76 0.76 32.0,
CPFSA.s .1.01Ft7.34-PFPix.5 3..99 3.59 24.1 12
WA) P7-..4,'.5 4.07 0.07 0.06 .<0.02 3..97
PFCA 2.94 7666.0 96e3 2/50 6.82
Perfitioroalkyi
Carbunlates
PF:rixA 8,05 5.64 3.95 0.62
(PFC,As
PFi-ipA 2,93 30.7 26.3 5.62 1.5
(Pg/1)
Fluorotelomets 62 FTS 0.42 <0.05 <0.05 <0.05 '0.05
IPMS (TOTAL) 7720 WOO 2150 194
Eletticai 1.29 0.16 6.11 .42.3
Con&ctivity
f mSif-TM
p..ht 5,79* 5.6a 6.7g 6.2
'Average of 146 grounthvarer s aro pies {pH range 3.9'5--g.56 EC f:.3t-ge 0.03-
26.6 rn aft m).
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Table 2.3tevErerfokaturefcifittvemstmi/ournenbta- per/
poignolyfludivapubst(RfetSs)(PRASMsad .14nAgsFeclAarkitiat
gfiVirtifftriefii4_44130W#8441Ast t NorftmLiNtAftmtrpM PK64/144,FAs chemicals
in bold.
CLASS SUBSTANCE Molecular Formula No. C
atoms
Perfluorobutane sulfonic add (PFBS) C4F5S03. 4
Perfluorcalk-yl Perfluoropentane sulfonic acid (PFPeSi CfF1lSO3-
5
Sulfonic Acids Perfluorohexane sulfonic acid (PFHxS) CÃF13503" 6
(PFSAs) Perfiuoroheptane sulfonic acid (PFHpS) C7F13503-
7
Perfluorooctane sulfonic acid (PFOSI CEF17503- 8
Perfluorodecane suifonlc acid (PFDS) C:cF2I5C.)3 9
Perfluorobutanoic acid (PFBA) c3F7COz- 4
Perfluoropentanoic acid (PFPeA) 5
Perfluorohexanoic acid (PFlixA) CF1CO 6
Perfluoroheptanoic acid (PFHpA) C5F13CO2- 7
Perfluoroalkyl
Perfluorooctanoic acid (PFOA) C7Fi5C:02: 8
Carboxylic
Perfluorononanoic acid (PFNA) CsF1,CO2- 9
Acids I.PFCAs1
Perfluorodecanoic acid (PFDA) FO 10
Perfluoroundecanoic acid PFunDA) 11
Perfluorodedecanoic acid (PFDoDA) CA.F2.3CO2. 12
Perfluorotridecanoic acid (PFTrDA) ClzF2.3CO2. 13
Perfluorotetradecanoic acid (PFTeDA) C,3Fz7C0z- 14
Perfluorooctane sulfonamide (FOSA) OsF;:s..,732NH2.
8
N-Methyl perfluorooctane sulfonamide CEFL7S02NHCH; 9
(MeFOSA)
N-Ethyl perf uorooctane sulfonamide 10
(EtFOSAI
N-Methyl perfluorooctane ;.:EF17502N(C.H2.):CH3OH 11
Perfluoroalk-yl
sulfonarridoethanol (MeFOSE)
Sulfonamides
(FOSAs)
N-Ethyl perfluorocctane CEF,7502N(CH2)30H 11
sulfonamidoethanol (EtFOSE)
N-Methyl perfluorooctane C3FI,S02.NCH3CHzCO: 11
sulfonamidoacetic acid (MeFOSAA)
N-Ethyl perfluorocctane OsF17SO:N(CH2):CH3CO2. 11
suifonarridoacetic acid EtFOSAA)
4:2 Fluorotelorner sulfonic acid (4:2FTS) Cif-14F5S03- 6
(n:2)
Fluorotelomer
6:2 Fluorotelorner sulfonic acid (6:2FTS) C3H4F13S03- 8
Sulfonic Acids
(FTSsl
8:2 Fluorotelomer sulfonic acid (8:2 FTS) CLcH4FL7S03- 10
10:2 Fl J orotelomer sulfonic acid C,2H4F2,503- 12
(10:2FTS)
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[00092]
Initial testing used the following sorbents: (1) a hemp seed protein powder
(HSP); (2) hemp seed (HS); (3) sphagnum peat moss; (4) humic acid (analytical
grade
(Sigma Aldrich chemicals)); (5) calcium carbonate (calcite sourced from DML
Lime,
Attunga, NSW); (6) various mixtures of sorbents 1, 2, & 5. As sorbents 3 & 4
did not show
any removal of PFAS contaminants, they were removed from the test schedule.
[00093]
Laboratory analysis returns the breakdown of all PFAS species found in a
sample as well as the total (sum) of all PFASs and the total of PFHxS + PFOS.
Existing
studies on PFHxS suggest that this chemical can cause effects in laboratory
test animals
similar to the effects caused by PFOS. However, based on available studies,
PFHxS
appears to be less potent in animal studies than PFOS. Consequently, PFHxS and
PFOS
concentrations are a reported as a combined concentration.
[00094] The
Commonwealth Department of Health has established health based
guidance values and currently the maximum drinking water values are 0.07
i.tg/L for
PFHxS+PFOS and 0.56 i.tg/L PFOA. These are the only PFAS species to have
guidance
values.
[00095]
Figure 1 shows the removal at high ionic strength (Water D; Table 1) of
total (sum) PFAS and PFHxS + PFOS. HSP by itself removed ¨90.8% of the initial
total
PFAS (2160 tg/L) and ¨96.7% of the initial PFHxS+PFOS (2.41 tg/L) giving a
final
concentration of 0.055 i.tg/L (PFHxs+PFOS) and ¨198.7
PFAS. It is evident that
calcite by itself performs poorly in comparison to HSP and that the addition
of calcite to
HSP does not change the amount of PFHxS + PFOS removed but increases the total
PFAS
removed by ¨3.1%.
[00096]
Figure 2 shows removal at high ionic strength for certain PFCAs
compounds, whereas Figure 3 shows removal at high ionic strength for certain
PFSAs
compounds. Figure 2 shows that, with the addition of calcite (1:1) to HSP,
there is a
defined trend in the removal of PFCAs, with removal increasing with decreasing
carbon
chain length. For example, with PFNA (9C (carbon chain)) there is no
difference in its
removal, with PFOA (8C) removal increased by ¨2.7%; PFHpA (7C) removal
increased
by ¨14.8%; and PFHxA (6C) removal increased by ¨32.3%.
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[00097] For the PFSAs (Figure 3) the addition of calcite has no effect on
PFOS
removal with final concentrations below the laboratory limit of reporting
(>99.9%
removal) with HSP alone. There is <1.4% difference in the shorter chain (6C)
PFHxS
removal indicating that the presence of calcite does not significantly affect
PFSA removal
by HSP.
[00098] Due to lack of sample volume, no calcite (alone) experiments were
done in
the low ionic strength series. Figures 4 to 6 shows the removal of PFAS from
low ionic
strength solution (Sample C, Table 1) using HSP and HSP + calcite at 100 g/L.
From
Figure 5 it is apparent that the low removal (-19.1%) of PFOA is erroneous
given that the
same sample (not shown) using only 70 g/L solid to liquid ratio indicated
¨69.9% removal.
[00099] The addition of calcite to HSP resulted in a PFOA removal >99.9%
(below
laboratory limit of detection) from an initial concentration of 969 [tg/L.
[000100] As found with the high ionic strength experiments, the addition
of calcite to
HSP appears to have a positive effect on the removal of PFCAs with increasing
removal
with decreasing chain length (with the exception of the PFOA error as
discussed above).
For example, Figure 5 shows no increase for the 10C (carbon chain) PFDA, 1.4%
increase
for PFNA (9C), 21.5% increase for PFHpA (7C), and 29.2% increase for PFHxA
(6C).
Figure 6 shows that the addition of calcite did not affect PFOS removal,
however, there
was a slight (-4.0%) increase in PFHxS removal observed at low ionic strength.
All other
PFAS species present in the initial control sample were removed to below the
laboratory
limit of reporting (Figs 5-6) after the addition of calcite to HSP.
[000101] To compare the PFAS removal ability of hemp seed powder to the
hemp
seed (not powdered) a series of comparative experiments were done. Figure 7
shows the
removal comparison at low ionic strength and it appears that HSP appears to
remove much
less total (sum) PFAS than HS. This is due to the erroneous PFOA result in
this experiment
(as discussed above) and therefore the total (sum) PFAS removal should be
disregarded. At
high ionic strength (Figure 8) HSP removed only ¨7.3% more total (sum) PFAS
than HS.
For the total amount of PFHxS + PFOS removed, less than ¨1% difference between
HSP
and HS was observed at high ionic strength. This was supported by the low
ionic strength
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results (Figure 7). Consequently, depending on cost it may be beneficial to
use HS rather
than the more refined HSP.
[000102] Figure 9 shows the removal of total PFAS and PFHxS+PFOS as a
function
of HSP solid-to-liquid ratio. As expected from a sorption reaction,
contaminant removal
increases with increasing mass with 100g/L HSP removing ¨96.7% PFOA to 0.22
pg/L
well below the Australian Drinking Water Guidelines (ADWG). However, despite
removing ¨98.7% of the initial PFHxS+PFOS, the final concentration (-2.12
tg/L) still
exceeds the ADWG of 0.07 Rg/L.
[000103] Figure 10 shows the overlay of three TGA test using analytical grade
PFOA,
unreacted hemp seed powder and HSP reacted with water Sample B. The top series
shows
as a function of time the mass loss reactions, the middle series shows the
heat flow of the
reactions, and the bottom series shows mass loss as a function of temperature
( C).
[000104] PFOA loses its entire mass (-99.92%) by 140 C with two exothermic
peaks at
¨65 C and 125 C.
[000105] Unreacted HSP appears to have only one major mass loss occurring
between
¨180-430 C. However, at ¨82.2% the mass loss is significant and reflects the
amount of
organic matter (protein) in the sample. In contrast the reacted HSP has a
total mass loss of
¨80.49% over three distinct regions (-42.6% between 210-260 C; ¨18.47%
between 300-
380 C; and ¨19.42% between 380-450 C) indicating that the sorption of PFAS
has
changed the bonding strengths of the organic (perhaps proteins) component in
the HSP.
The total mass lost is within 1.5% of the un-reacted HSP indicating that the
spent HSP
appears to be completely destroyed by ¨450 C.
EXAMPLE 2
[000106] Approximately 50L was obtained from monitoring well MW187s at
Williamstown RAAF Base, NSW, Australia. Table 3 lists the major PFAS analytes
and
concentrations of this sample as determined by ALS laboratories, Sydney, NSW,
Australia.
The term PFAS is used to describe all per- or polyfluoroalky species, which
can be divided
into subclasses and individual species as shown in Table 2.
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Table 3. Major PFAS analytes found in ground water from monitoring well (MW)
187 as used in Example 2.
Analyte Grouping _____________________ Anabite MW187s
Perflucroalkane PFOS 91/
Sulfonates PFHxS 20/
IPFSA5) PFBS 3
IPFOS+PH-IKS 11
PFCA 4.3
Perflucroalkyl
PFbixA 6.3
tarboxylates
PF HpA 2.18
(P FCAs)
PFBA 3.3
(tg/L)
Fluorotelomers 6:2 FTS <0.05
(1.tg/L)
IPFAS (TOTAL) 194
[000107] An experimental methodology as provided in Example 1 was followed
wherein
soy protein isolate powder (SPI) (natural; sourced from a health food store)
is compared to
removal using hemp seed powder (HSP). Experiments using groundwater from
MW187s
were conducted on both protein powders at equivalent solid-to-liquid ratios
(100g/L) to
compare any differences in removal.
[000108] Figure 11 compares the removal of total sum PFAS compounds as well as
the
total sum of PFHxS and PFOS for both HSP and SPI. As indicated HSP and SPI
display
similar efficacy as adsorbents, with HSP removing -2.6% more total PFAS than
SPI,
whereas the difference in PFHxS and PFOS removal showed <1% difference.
[000109] Referring now to Figure 12, shown is a comparison of the removal of
selected
PFCAs for HSP and SPI. Figure 12 indicates that the efficacy of HSP may be
generally
greater than SPI in regards to PFCAs, with PFOA and PFPeA being removed below
the
laboratory limit of reading (<LOR) using HSP as an adsorbent, as indicated by
the * in
Figure 12. PFOA and PFPeA removal using HSP was about >20.5% and about >26%
higher respectively compared with using DPI as an adsorbent. PFHxA was about
>8%
greater for HSP compared to SPI.
[000110] Referring now to Figure 13, shown is a comparison of the removal of
selected
PFSAs for HSP and SPI. Figure 13 indicates that little difference exist in the
ability of
HSP and SPI to remove PFSA species, with >99% PFOS removal observed
irrespective of
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the sorbent and >95% PFHxS removed by HSP and 92.5% removed by SPI.
EXAMPLE 3
[000111] Groundwater from monitoring well MW187s was diluted by volume to
achieve
a concentration of 10%, 25%, 50% and 100% (undiluted) of the initial
groundwater
according (Table 3). Sorption isotherms were then developed for HSP and SPI at
a solid to
liquid ratio of 100g/L.
[000112] The adsorption distribution coefficient (Kd) is used environmentally
to estimate
the removal of a contaminant during treatment with a given sorbent material.
Kd is
determined from the analysis of a sorption isotherm where the amount of
contaminant
removed per mass of sorbent (Cs; [tg/kg) is compared to the final
concentration of
containment in solution (Ce; [tg/L). Accordingly, Kd is expressed in units of
L/kg.
[000113] For a linear relationship Cs=KdC, with high Kd values indicating that
the
sorbent has a high affinity for the containment. Other sorption isotherms
relationships
exist such as the Freundlich or Langmuir isotherm but these describe non-
linear
contaminant sorption. In the experiments presented herein, for all PFAS
species present
the removal over the concentration range tested general followed a linear
response.
[000114] The linear isotherm for PFOA and PFBA with HSP showed an "infinite"
removal response as the final concentration, in all cases, was reduced to
below the
laboratory limit of reporting. Table 4 below gives the Kd values obtained for
PFOS and
PFOA using HSP are very large (>1000) and infinite respectively, however, the
true value
for PFOA will depend on further experiments using higher initial
concentrations of PFOA.
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Table 4 PFAS partitioning coefficients using hemp protein powder (HSP) and soy
protein isolate (SPI) at
100g/L
PFAS species Kõ (L/kg) using HPP K. (L/kg) using WI
PFOA "inf nite" 19.7
PFRA "inf nite" "infinite-
PFf-ixA 35.2 23.2
PFOS 1C40.5 765.6
37.7 26.3
PHxS 175.8 125.5
EXAMPLE 4
[000115] Using groundwater obtained from the most contaminated monitoring
well
(MW187s) identified at Williamtown RAAF base, batch sorption tests were
carried out to
determine the respective sorption isotherms for the individual PFAS
components. An
additional sample taken from Moor's Drain adjacent to the Williamtown RAAF
base was
spiked with analytical grade PFOA and used in some experiments, as previously
described.
Table 5 shows the PFAS concentrations in each of these samples.
Table 5 Major PFAS analytes in groundwater from monitoring well MW187s at
Williamtown, NSW and a
PFOA spiked water sample obtained from Moor's Drain, Williamtown.
Analyte Grouping Analyte Moor's Drain Williamtown
(spiked with RAAF
PFOA) groundwater
MW187s
Perfluoroalkane PFOS 2.94 130.0
Sulfonates PFHxS 1.05 32.0
(PFSAs) SPF0S+PFHxS 3.99 162
(vig/L) PFBS 0.07 3.97
PFOA 766 mg/L 6.82
Perfluoroa I kyl
Ca rboxylates
PFHxA 5.64 9.34
(PFCAs)
PFHpA 30.7 1.5
(vig/L)
Fluorotelomers 6:2 FTS <0.05 <0.05
(vig/L)
SPFAS (TOTAL) 770 mg/L 194
Electrical 0.16 <1
Conductivity
(ms/cm)
pH 6.68 6.8
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[000116] The individual chemicals belonging to PFAS classes of PFCAs, PFSAs,
sulfonamides and telomeres are shown above in Table 2. No chemicals belonging
to the
sulfonamide or telomere classes were detected for Williamtown, i.e. all were
below the
laboratory limit of reporting.
[000117] Batch tests were conducted in 120 mL PFAS approved (polypropylene)
plastic ware, capped and left for at least 3 days in an end-over-end stirrer
to equilibrate at
¨20 C. Blanks were included in each batch test using de-Ionized (DI) water or
DI water
made up to ¨45 mS/cm with KC1 for high ionic strength tests. All PFAS analyses
were
done at ALS laboratories, Sydney (NATA accredited) using modified USEPA method
315
for a standard suite of 28 PFAS analytes as listed in Table 2.
[000118] At the end of the equilibration period, samples were centrifuged
at 20 C and
the supernatant decanted into clean polypropylene jars. These were
refrigerated until
transfer to a NATA accredited lab (ALS laboratories) typically the same day
(or <24
hours). A small aliquot (<5 mL) of each sample was taken for pH, electrical
conductivity
(EC). The remaining solid was subsampled (<40 mg) and analysed by
thermogravimetric-
differential scanning calorimetry (TGA-DSC) using a Mettler Toledo Star TGA-
DSC
under an 02 or N2 atmosphere at 40 mL/min and a temperature gradient of 10 C
per minute
from ¨30 to 1080 C.
[000119] Total Oxidizable Precursor (TOP) Analysis was conducted. The TOP
analysis
transforms the numerous PFAS precursors that generally exist in a contaminated
sample to
those compounds detected as part of the standard suite of analytes. This gives
a worst case
scenario as it "reveals" the potential unidentified hidden PFAS chemicals that
may exist in
a sample.
[000120] However, in accordance with other publications and analysis of the
results
obtained thus far, the present inventors have reservations on the reliability
of the laboratory
TOP analyses. Other publications (https://www.envstd.com/top-analysis-more-to-
consider-
when-monitoring-polyfluorinated-alkylated-substances/) indicate that further
research
using TOP analysis is needed to define its limitations. Furthermore, TOP
analysis should
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not be used at this time as proof of total PFAS degradation, or as a
quantitative indication
for human or ecological risk assessment.
[000121] Analysis of results pre and post TOP (identified herein as "¨TOP"
or
"+TOP") indicate that TOP analysis may give results that are false or
misleading. For
example, experiments without TOP analysis show concentrations of PFOS ¨130
[tg/L, but
with TOP ¨76.5 [tg/L. Additionally, percentage removal calculations vary
widely
depending on which result set (+TOP or ¨TOP) are used. Further investigation
into the
validity of TOP analysis is required. Nevertheless, as the TOP analysis
appears to be a
requirement for publication and acceptance of remediation data, it was carried
out and the
results are included in the present application.
[000122] The overall analysis procedure including the addition of the TOP
analysis is
shown in Figure 14. TOP analysis was done (indicated by +TOP) on solids and
aqueous
phases. Aqueous phases were also analysed for non-oxidised (-TOP) sampled to
enable the
amount of precursor PFAS compounds in the sample to be determined.
[000123] Batch sorption tests were carried out according to the
experimental matrices
of Tables 6 and 7 below. Table 6 represents the experimental matrix for low
(natural) ionic
strength batch tests using MW187s groundwater. The groundwater was either
undiluted
(100%) or diluted to 50, 25, 10, or 1% and mixed with hemp seed powder (HSP)
to give a
final solid to solution ratio of 0 (control) to 200 g/L. In addition to these
experiments,
blanks using de-ionized water at each ionic strength to determine PFAS
sources/sinks from
sorbent were also tested.
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Table 6. Experimental matrix for hemp protein powder at low (natural) ionic
strength as a Junction of solid
to liquid (51) ratio.
S:L ratio Low Ionic Strength MW187s groundwater
0 (control) 100% ,( 50% ,( 25% ,( 10% ,( 1% ,(
/ /00% V 50% V 25% V 10% V 1%
100% ,( 50% ,( 25% ,( 10% ,( 1% ,(
25 100% 50% 25% 10% 1%
50 100% ,( 50% ,( 25% ,( 10% ,( 1% ,(
75 100% 50% 25% 10% 1%
100 100% ,( 50% ,( 25% ,( 10% ,( 1% ,(
200 100% ,( 50% ,( 25% ,( 10% ,( 1% ,(
[000124] Table 7 shows the experimental matrix for the high ionic strength
experiments using MW187s groundwater to determine the effects of salinity on
PFAS
removal using HSP. Potassium chloride was added to the respective groundwater
dilutions
to achieve a final electrical conductivity of ¨49 mS/cm. The presence of a
tick symbol
indicates completed experiments; conversely, those without a tick symbol were
either not
done or replaced. For example, solid to liquid ratio tests using 1.0g/L HSP
were completed
in lieu of 25 and 75g/L tests. In addition to these, blanks using de-ionized
water at each
ionic strength to determine PFAS sources/sinks from sorbent were also tested.
Table 7. Experimental matrix for hemp seed powder (HSP) at high ionic strength
(-50 mS/cm) as a function
of so lid to liquid (5:0 ratio.
S:L ratio High Ionic Strength MW187s groundwater
0 (control) 100% ,( 50% ,( 25% ,( 10% ,( 1% ,(
/ 100% 50% 25% 10% 1%
10 100% ,( 50% ,( 25% ,( 10% ,( 1% ,(
25 100% 50% 25% 10% 1%
50 100% ,( 50% ,( 25% ,( 10% ,( 1% ,(
75 100% 50% 25% 10% 1%
100 100% ,( 50% ,( 25% ,( 10% ,( 1% ,(
200 100% ,( 50% ,( 25% ,( 10% ,( 1% ,(
[000125] From these experiments, Figure 15 graphs the removal at low
(natural; ¨2
mS/cm) ionic strength of PFOS, PFOA, sum of (PFHxS + PFOS), and sum of PFAS
from
100% (undiluted) MW187s as a function of HSP solid to liquid ratio. Under the
test
conditions, it is evident that ¨50 g/L is sufficient with removals of ¨99.8%
PFOS, 98.3%
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PFOA; 99.5% E(PFHxS+PFOS), and 98.7% E(PFAS) without TOP analysis (initial
concentrations ( g/L) PSO ¨130; PFOA ¨6.82; E(PFHxS+PFOS) ¨162; E(PFAS) ¨194).
[000126] Figure 16 shows the effect of high ionic strength (approximately
sea water
salinity; ¨49 mS/cm) on PFAS removal from 100% (undiluted) MW187s (without TOP
analysis). Although good removal is experienced at 50 g/L, an increase to 100
g/L does
increase PFOA removal by ¨12% and ¨7% for the remaining PFASs (initial
concentrations
( g/L) PSO ¨130; PFOA ¨6.82; E(PFHxS+PFOS) ¨162; E(PFAS) ¨194). This indicates
the possibility of a suppression in removal at higher ionic strength.
EXAMPLE 5
[000127] To refine the HSP mass required for optimal PFAS removal, a
series of tests
were done in a sequential PFAS removal system. In total, seven batches
consisting of a two
stage removal (A and B) at various solid to liquid ratios were carried out
using 100%
(undiluted, low ionic strength) groundwater. For example, Experiment 1 (stage
A)
consisted of ¨120 mL of undiluted groundwater mixed for 48 hours with 10 g/L
HSP.
After stage A was completed, the vial was centrifuged and the supernatant and
HSP
separated. A 60 mL aliquot of the supernatant was transferred to a vial
containing HSP at
g/L (0.6g in 60 mL solution) to begin experiment 1 (stage B). The remaining
stage A
supernatant and used HSP were then refrigerated. Stage B samples were then
mixed for a
further 48 hours before being centrifuged and separated. All samples were then
sent to
ALS labs for TOP analysis (liquid and solid) (60 mL was used as this is the
volume
required by the laboratory for analysis).
[000128] Figure 17 shows the PFAS removal results for the smallest HSP
solid-liquid
ratios of 10 g/L for stage A & B removal. It is clear that PFOS has a very
high affinity for
HSP with 88.7% removed at stage A and >99.1% removal after stage B. PFOA,
however
only showed a 63% removal after stage B. This is consistent with medical
literature which
identifies PFOS as being the most tightly bound to human blood proteins.
[000129] Figure 18 uses two 50 g/L stages and shows that by the end of
stage B,
PFOS has been removed to below the laboratory limit of reporting (<0.1 g/L)
(indicated
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by *). Note this LOR is above the current Australian drinking water guidelines
(ADWG) of
0.07 pg/L and further work may be required to enable a more accurate analysis.
Additionally, the concentration of PFOA was reduced to >93.7% with a final
concentration
of 0.53 g/L which is almost exactly the current ADWG limit of 0.56 g/L
(indicated by
**). The sum of PFHxS + PFOS was reduced from 122 to 0.42 g/L, which is below
the
recreational concentration limit of 0.7 g/L.
[000130] Figure 19 represents PFAS removed using two 100 g/L steps with
the
concentrations of PFOS and E(PFHxS+PFOS) reduced to below the laboratory limit
of
reporting (0.1 g/L) and PFOA reduced to 0.18 g/L. Clearly, at stage A, there
is little to
gain in using HSP at 100 g/L over 50 g/L (Figures 18 vs 19). The optimal solid
to liquid
ratio for PFAS removal may thus be further investigated, for example, a three
or four
g/L stage treatment system. The number of tests can be reduced by modelling
the
reactions using data obtained from the reaction kinetics and sorption
isotherms.
EXAMPLE 6
[000131] Tables 8 and 9 outline experiments to determine the kinetics of
PFAS
removal using HSP and the effect (on kinetics) of adding calcite to the
system. During
experimentation, aspects of the two tables were combined to produce results
that elucidate
the kinetics of the reactions as a function of ionic strength and calcite
addition to HSP. At
this stage, three calcite solid to liquid ratios (1, 10, & 100 g/L) using two
different sized
calcite fractions (<150 jim & 1.18-2.36mm) have been tested using either low
or high ionic
strength or 100% (undiluted) groundwater.
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Table 8. Experimental matrix for sarbent I (HSP) & 5 (calcite) at various
solid to liquid ratios and ionic
strength
High Ionic Strength Low Ionic Strength
51:55 ratio Sample C Concentration Sample B
Concentration
Six 1:2
100% 50% 25% 10% 1% 100% 50% 25% 10% 1%
Six 1:1
100% 50% 25% 10% 1% 100% 50% 25% 10% 1%
Six 1:0.25
100% 50% 25% 10% 1% 100% 50% 25% 10% 1%
Sly 1:2
100% 50% 25% 10% 1% 100% 50% 25% 10% 1%
Sly 1:1
100% 50% 25% 10% 1% 100% 50% 25% 10% 1%
Sly 1:0.25
100% 50% 25% 10% 1% 100% 50% 25% 10% 1%
Tcble 9. Experimental matrix for kinetics experiments
Sorbent 1 Sorbent mix 1&5
High Ionic Strength Low Ionic Strength High Ionic Strength
Low Ionic Strength
Sample C Sample B Sample C Sample B
TIME Concentration Concentration Concentration Concentration
¨5
min 100% 10 or 1% 100% 10 or 1% 100% 10 or 1%
100% 10 or 1%
¨15
min 100% 10 or 1% 100% 10 or 1% 100% 10 or 1%
100% 10 or 1%
¨30
min 100% 10 or 1% 100% 10 or 1% 100% 10 or 1%
100% 10 or 1%
1 hr 100% 10 or 1% 100% 10 or 1% 100% 10 or 1%
100% 10 or 1%
2 hr 100% 10 or 1% 100% 10 or 1% 100% 10 or 1%
100% 10 or 1%
8 hr 100% 10 or 1% 100% 10 or 1% 100% 10 or 1%
100% 10 or 1%
24 hr 100% 10 or 1% 100% 10 or 1% 100% 10 or 1%
100% 10 or 1%
[000132]
Data obtained from the experiments (Tables 8 & 9) were fitted to the selected
models namely pseudo-second order kinetics (PSO), intra-particle diffusion
(IPD) and Hill
models. For simplicity, only the PSO model is described here, although the
nature of the
other models are well within the common general knowledge of the person
skilled in the
art.
[000133] The
Pseudo-second order (PSO) kinetics model (HO AND McKAY, 1998) is
given by:
t _______________________________________ 1 t
- +
q,
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where q ( g/kg) is the amount of fluoride removal at time t, qe ( g/kg) is the
sorption
capacity at equilibrium, lcpse is pseudo-second order rate constant (kg/
g/hr). The PSO
instantaneous sorption rate hps0( g/kg/hr) (HO AND McKAY, 1998) is defined by:
lips =Ifpsoqe2
with the reaction half-life (t0.5) or the time for 50% maximum removal to
occur is given by:
1
t ¨
0 5 kpsoqe
[000134] In order to identify the most suitable model to describe the data,
the
correlation coefficient (R2), AIC (Akaike Information Criterion) and BIC
(Schwarz
Bayesian Information Criterion) are often used for model selection (TURNER et
al., 2014).
The R2 is efficient in evaluating the goodness-of-fit of each model to the
data, however, it
is not a good method for comparing the fits between models with differing
numbers of
parameters. As only one model is presented here, the R2 value is presented as
a measure of
model fitting. The closer the R2 value is to 1.00, the better the model fit.
[000135] Figures 20A to 20D show the percentage removal kinetics of PFCA
using
HSP from MW187s groundwater and the various treatments (i.e. calcite addition
and ionic
strength). Figure 20A shows removal kinetics at low (natural) ionic strength
with HSP
only; Figure 20B is for low (natural) ionic strength with HSP and 1.00 g/L
calcite (<150
p.m); Figure 20C is for high ionic strength with HSP only; Figure 20D is for
high ionic
strength with HSP and 1.00 g/L calcite (<150 p.m). All results are from TOP
analysis. It
can be seen that with HSP alone (Fig 20A) there is a distinct decrease in
removal for PFBA
with increasing time. However, other experiments (not shown) also show high
variability
in PFBA concentrations and it is unknown if this is a general problem,
specific for PFBA
detection, or simply analysis error due to the small concentrations of PFBA
present.
Additionally, it is possibly an error introduced via the TOP analysis step
where the use of
more (or less) of the persulfate oxidant can induce significant changes in the
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concentrations of short chain PFASs. Consequently, all future results should
scrutinise
PFBA concentrations closely.
[000136] Percentage removal kinetics of PFSAs are analogously shown in
Figures 21
A-D.
[000137] In general, the removal of PFCAs (Figure 20) and PFSAs (Figure 21)
are
rapid (< lhour) with excellent removals, particularly for the PFSAs, likely
due to their
higher affinity for the hemp proteins as compared to the PFCAs. The effects of
calcite
addition and ionic strength are discussed in more detail below in conjunction
with the
pseudo-second order modelling.
[000138] Figures 22 and 23 show the percentage removal of PFCAs and PFSAs
respectively after six days contact time (144 hours) with HSP alone, and HSP
with calcite.
These were repeated for low and high ionic strengths at various time steps.
For comparison
activated carbon (manufactured by Norit and supplied by Sigma Aldrich) was
used at the
same solid to liquid ratios at low and high ionic strength. There is no
kinetic data for the
AC at this time. Note: the AC carbon used here is not the same as those
generally used
(e.g. Calgan Filtrasorb) for PFAS removal treatment plants.
[000139] Results in Figure 22 & Figure 23 show that for the same mass of
HSP (100
g/L), the addition of 1.0 g/L of calcite powder (<150 i_tm particle size)
increases the
removal of short chain PFCAs (Figure 22). For example, assuming the
concentration data
is correct for PFBA (4 carbon), its removal increased by ¨17% to below the
limit of
reporting (<0.1 g/L) after the addition on calcite. However, the removal of
all other
PFCAs appears to decrease following calcite addition with PFPeA reduced by
¨32%. The
addition of calcite appears to also suppress shorter chain PFSA removal with
¨10-15%
decrease in removal observed for PFBS (4 carbon) and PFPeS (5 carbon). No
significant
changes from the addition of calcite were observed for the remaining PFSAs.
However, in
light of the discussion concerning PFBA above, laboratory data for all shorter
chain PFASs
(in particular 4 carbon) generally show high variability, indicating that
additional replicates
must be done before a definitive conclusion can be reached on the effect of
adding calcite
to the system.
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[000140] In addition to the hpso model parameter, also obtained from the
model were
the reaction half-life (t0.5) and equilibrium sorption capacity (qd as
described at [000133]
and tabulated in the following sections. It should be noted that these
parameters are based
on the particular reaction conditions described. Under the test conditions it
can be seen that
the reaction half-lives are very quick being on the order of minutes. In Table
10 to Table
13 the slowest removal of PFOA (high ionic strength, HSP only; Table 12) was
0.22 hours
indicating that 13.2 minutes was required to remove 50% of the initial
concentration. In
comparison, the slowest PFSA was the 4C PFBS (Table 10) requiring 35.4 minutes
(to.5
-0.59 hr) with predicted PFOS half-life rates all less than 2.4 minutes. This
is in stark
contrast with current technologies such as various activated carbons which
appear to take
days for equilibration, even at much higher PFAS concentrations than tested
here. This is
significant as the rate of reaction is generally proportional to the initial
concentration of
contaminant.
Table 10. Kinetic made/ (PSO) pararneter5 for PFAS removal by I-1,5P a low
(natural) ionic strength, with TOP analysis.
Not NA mdicare,s model did not fit. NA . model did not fit,
q, R2
PFAS hpso (Kg/kg/hr) kpso (kg/ g/hr)
t05 (h)
(1-1g/kg)
P113 S 90.4 3.12 x 10-2 ___________________________
53.8 0.59 0.981
PFPeS 146.9 6.0x102 49.3 0.33 0.981
PFHxS 1582.1 2.6x102 248.7 0.16 0.996
PFHpS 1980.8 66.9 x 10-2
54.4 0.03 0.999
PFOS 1.88x104 3.23x10-2
759.0 0.04 0.999
E(PFAS) 2.82x104 9.6 x10-3
1717.7 0.06 0.996
E(PFHxS+PFOS) 1.52x104 1.4x102 1010.5 0.07 0.999
P1,13 A NA NA NA NA 0.337
PFPeA 2.76x1016 2.6x1012 102.7 3.7x10-15
0.911
PFHxA 2265.7 2.2x10-2
323.9 0.14 0.998
PFHpA 267.6 0.29 30.4 0.11 0.994
PFOA 612.7 0.22 52.3 0.08 0.972
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Table 11 Kinetic model (PSO) parameters for PFAS removal by HSP with 1.0 g,i1
calcite (<150 iT!]m) at low (natural) ionic
strength, with TOP analysis.
q, R2
PFAS hp,,, (Kg/kg/hr) ki,õ (kg/ g/hr)
to 5 (h)
(1-1g/kg)
P1,13S 296.1 0.13 47.7 0.16 0.995
PFPeS 266.2 0.12 46.7 0.17 0.990
PFHxS 2357.9 3.9x10-2 243.3 0.10 0.996
PFHpS 2444.2 0.83 54.2 0.02 0.999
PFOS 24859.0 4.3x10-2 757.6 0.03 0.999
E(PFAS) 67895.6 2.2x10-2 1727.8 0.03 0.999
E(PFHxS+PFOS) 21458.1 2.1x10-2 1003.8 0.05 0.999
P1,13 A >3x10" >1x1017 75.3 <1x1019 0.942
PFPeA 11785.2 0.98 109.4 0.01 0.999
PFHxA 12021.6 0.12 315.8 0.03 0.998
PFHpA >1x102 >1x1017 30.4 <2x1019 0.996
PFOA >1x10" >3x1014 52.4 <5x10-17
0.963
Table 12. Kinetic mode (PSO) parameters for PFAS removal by HSP at high (-49
rnSicin) ionic strength, with TOP
analysis..
q, R2
PFAS hp,,, (Kg/kg/hr) lc (kg/ g/hr) to
.s (h)
(1-1g/kg)
P1,13S 457.8 0.18 50.6 0.11 0.997
PFPeS 672.4 0.31 46.4 0.07 0.999
PFHxS 3973.5 0.07 239.2 0.06 0.999
PFHpS 1773.2 0.63 53.1 0.03 0.999
PFOS 38200.8 0.07 726.7 0.02 0.999
E(PFAS) 41410.1 0.01 1676.7 0.04 0.999
E(PFHxS+PFOS) 33671.1 0.03 968.9 0.03 0.999
P1,13 A >3x10" >5x1014 72.3 <10-17
0.928
PFPeA 3207.6 0.27 107.8 0.03 0.999
PFHxA 5501.8 0.06 298.4 0.05 0.998
PFHpA 213.6 0.25 29.0 0.14 0.997
PFOA 230.9 0.08 51.9 0.22 0.981
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Toige13, Kinetic model (PSO) parameters for PFAS removal by HSP with 1.0 el.
calcite (<150E:77) at high (-49 mS/crn)
Ionic strength, with TOP analysis.
q, R2
PFAS h,, (Kg/kg/hr) kpõ(kgli-tglhr)
t05 (h)
(1-1-gilcg)
PFBS 2062.1 0.88 48.3 0.02 0.985
PFPeS 899.7 0.41 46.6 0.05 0.999
PFHxS 7415.9 0.13 236.5 0.03 0.999
PFHpS 3622.6 1.30 52.7 0.01 0.999
PFOS 38968.8 0.07 725.1 0.02 0.999
E(PFAS) 61711.6 0.02 1673.4 0.03 0.998
E(PFHxS+PFOS) 44322.6 0.05 964.7 0.02 0.999
PF13 A >4x1021 >6x1017 78.2 <2x10-2 0.936
PFPeA 3711.1 0.32 108.1 0.03 0.999
PFHxA 9954.6 0.12 293.7 0.03 0.996
PFHpA 273.3 0.33 28.9 0.11 0.981
PFOA 304.1 0.11 53.6 0.18 0.961
[000141] Experiments using Norit activated carbon (AC) under the same
conditions (solid-liquid ratio, PFAS concentration, reaction time (6 days)
etc) show for
PFCAs (Figure 22) that HSP competes very well with the AC, with PFOA removal
at both
high and low ionic strength, within 5% of AC. PFPeA appears to have less
removal
(-30%) using HSP than AC and further tests would be required to confirm this.
The
Norit AC also appears very good for PFSAs (Figure 23), particularly for the
short chain
PFBS and PFPeS, which appears to contradict current literature indicating that
AC is not
suitable for short chain PFASs. For PFOS and PFHxS however, HSP appears to be
equal
to, or better than, the AC with HSP+calcite showing a removal of within 5% of
the Norit
AC.
[000142] Further comparison of the differences caused by the addition
of calcite to
HSP can also be derived from the kinetics experiments (Tables 10 to 13).
Fitting the
pseudo-second order (PSO) model to the data allows the calculation of the
instantaneous
sorption parameter (hps0). The PSO model for instantaneous sorption rate (h)
as a function
of PFSA carbon chain length (for PFBS (4C), PFPeS (5C), PFHxS (6C), PFHpS
(7C),
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PFOS (8C)) is shown in Figure 24. For the short chain PFAS, the rate of
removal based on
hpso increases with the addition of calcite (e.g. PFBS Table 10 vs Table 11),
and increases
with increasing ionic strength (e.g. PFBS Table 10 vs Table 12), and even
quicker again at
high ionic strength with calcite (e.g. PFBS Table 10 vs Table 13). Overall,
the rate of
removal increases with chain length indicating that PFOS (8 carbon chain)
removal is the
fastest (there appears to be no concomitant trend with the PFCAs). As the
largest PFAS
chemicals sorb the fastest, this indicates the possibility (without wishing to
be bound by
theory) of different binding positions for each PFAS on the protein. Although
all PFASs
show very rapid removals, using HSP alone is the slowest with the addition of
calcite and
salinity increasing the removal rate. Without wishing to be bound by theory,
this is
possibly attributed to the partial denaturation and the opening up of sorption
sites within/on
the HSP globular proteins.
EXAMPLE 7
[000143] To describe the behavior of the adsorption process up to the
equilibrium or
stabilization point, adsorption isotherms are used. Sorption isotherms were
fitted with the
Freundlich (equation 1) or Linear model (equation 2):
S = Ef e4 .............................. (eqn 1)
S = KeC ............................... (eqn. 2)
where S ( g/kg) is the sorbed concentration, Ceq ( g/L) is the concentration
remaining
in solution, K, and Kd (( g/kg)/( g/L)) are the Freundlich or linear
partitioning constants,
and 6 (-) is the linearity parameter. The model fitted all isotherms
adequately, and there
was no need to consider more complex models (potentially bringing a risk of
over
parametrisation). Note: The partitioning coefficient Kd, is a single parameter
which, under
identical experimental conditions, concisely summarizes the removal ability of
a sorbent
(protein powders herein).
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[000144]
Figure 25 shows the PFAS removal isotherms for PFOS, E(PFAS), and
E(PFHxS+PFOS). Note: PFOA could not be plotted as all concentrations were
below limit
of reporting (<0.1 ug/L) which gives an infinite isotherm. The isotherms
plotted show a
linear fit as the initial concentrations used in the test groundwater are not
sufficient to use
all possible sorption sites at under the test conditions (100 g/L HSP).
Therefore, no
prediction as the maximum sorption capacity of HSP can be made from an
isotherm as yet,
and further testing using concentrations much greater than found in the
groundwater are
required.
[000145]
Even though the isotherms (Figure 25) have not yet achieved maximum
removal for any PFAS, the geochemical model used to plot the kinetics
reactions can be
used to predict the maximum PFAS removal designated as qe (Table 10 to Table
13). In
addition to the tabulated data, modelling of the maximum removal in terms of
mass of
PFAS removed per gram of solid can be seen in Figures 26 A-F along with the
95%
confidence intervals as derived from the model fitting process. PFOA shows a
maximum
removal of ¨ 60 g/kg, PFOS ¨750 g/kg, sum(PFHxS+PFOS) ¨1000 g/kg, sum(PFAS)
¨1750 g/kg. It should be noted that the model is predicting these values
based on the
current concentration limited data range, and it is expected that these will
increase with
further experiments. Interestingly, a single test using 100g/L HSP and a
spiked sample of
water obtained from Moor's Drain, Williamtown (Table 5, Initial[PFOA] ¨766,000
g/L)
showed a removal of 75.2% or 5,743 g/g, far exceeding the current predicted
¨60 g/kg
(Figure 26A).
[000146]
Sorption coefficients (K, or Kf) L/kg) were calculated using experiments
carried out with analytical grade PFOS solutions and/or experiments using
groundwater
from monitoring well MW187s at Williamtown RAAF base. The best fit based only
on
experiments with the analytical PFOS (which also contains PFHxS) solutions
(Figure 27;
triangles) was obtained using the Freundlich isotherm. Other data obtained
from all
groundwater experiments completed thus far have been overlaid and demonstrate
the
consistency of the results irrespective of the source of the PFAS, or HSP dose
rate.
EXAMPLE 8
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[000147]
Based on the removal isotherm produced using results from 29 samples
including both pure PFHxS+PFOS solutions as well as groundwater, a predictive
model
was generated in Microsoft Excel for the optimal sequence for PFHxS+PFOS
removal
using HSP. Using all 29 experiments the best fit Freundlich equation resulted
in the Kf =
405.4 and 6 = 1.0428 (R2 ¨0.9531). This model predicts the optimal hemp
protein powder
dose rate required to achieve removal to below the current Australian drinking
water
guideline of 0.07 g/L (70 parts per trillion (ppt)).
[000148]
Using a sequential stirred-reactor treatment sequence, the model indicates
seven batch reactor steps are required for the treatment of the groundwater
sourced "as is"
from MW187s. Figure 28 is a schematic diagram of sequential batch reactors;
influent
solution enters from the top of the vessel. Effluent solution from the bottom
becomes the
influent solution for the next batch reactor. Model results for various dosing
scenarios are
shown in Table 14 to 16. The results show that the optimal dose rate appears
to be ¨31 g/L
in total over seven batch reactors. By increasing the dose rate slightly to
¨40 g/L total, the
number of batch reactors can be decreased to five (Table 15), and if 75 g/L
total dosing is
used, only 3 steps is required to achieve the drinking water target (Table
16).
Table 14. Hemp protein powder dose rate and modeled (predicted) Influent and
effluent PFHxS+PFOS concentration for
each sequential batch reactor. Total HSP 31 g/L
Batch Reactor Hemp Protein Powder Influent concentration Effluent
concentration
dose (g/L) (ug/L) (pg/L)
A 5 122 33.90
33.9 9.81
5 9.81 2.94
5 2.94 0.916
5 0.916 0.295
4 0.295 0.098
2 0.098 0.034
Cumulative HSP mass 3/
(g/L)
Table 15. Hemp protein powder dose rote and modeled (predicted) Influent ond
effluent PFHxS+PFOS concentration _for
eaca setpentiai batch reactor. Total HSP 40
Batch Reactor Hemp Protein Powder Influent concentration Effluent
concentration
dose (g/L) (pg/L) (pg/L)
A 10 122 19.70
19.70 3.39
10 3.39 0.622
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D 5 0.622 0.202
0.202 0.068
Cumulative HSP mass 40
'g/L)
Table 16. Hemp protein powder da5e rate and modeled (predated) influent dile,'
effluent PF1-1,64-PFOS concentration for
each sequential botch reactor, Teta/ HSP 75 g4_
Batch Reactor Hemp Protein Powder Influent concentration Effluent
concentration
dose (g/L) (j.tgA) (pg/L)
A 25 122 8.72
25 8.72 0.692
25 0.692 0.061
Cumulative HSP mass 75
(g/L)
EXAMPLE 9
[000149] Thermal destruction of sorbent and bound PFAS was assessed as
follows.
[000150] Fourier transform infrared (FTIR) spectroscopy is a non-
destructive technique
that allows a biochemical fingerprint of a sample to be taken. It is routinely
applied in the
areas of biology, chemistry, and medicine to characterize complex biochemical
systems
from cells and subcellular compartments to whole organisms.
[000151] Figure 29 and Figure 30 show the thermogravimetric (TG) and heat
flow
curves during combustion of HSP exposed to de-ionised water only (Figure 29)
and HSP
exposed to PFOS at an initial concentration of ¨9.6 mg/L (Figure 30). In both
curves, the
mass losses by 700 C are within 2% at ¨92% with the remaining 8% identified
by FTIR
(see below) as amorphous silica (glass/sand). When exposed to PFOS, the heat
required to
destroy the HSP increases from ¨550 C to ¨650 C with the exothermic
(positive) heat
flow maxima shifting from ¨300 C to ¨550 C. Without wishing to be bound by
theory,
this is potentially because of the higher temperatures required for the
destruction of C-F
bonds in the PFOS. The shift to higher temperatures for HSP destruction after
exposure to
PFOS is consistent with the addition (via sorption) of chemical ligands (PFOS)
to the HSP
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proteins. This is supported by the FTIR data (Figure 31) which shows the infra-
red
difference spectra of HSP samples exposed to three different concentrations of
PFOS.
[000152] The idea behind difference spectra is to see the changes of a
specific group
against the absorption background of several other absorbing groups in the
same spectral
region. Infrared difference spectra are the result of subtracting a spectrum
of the protein in
state A from a spectrum of the protein in state B. In this way, only groups
that actively
participate in the reaction are evident, whereas the absorbance of groups that
do not
participate in the reaction are cancelled in the subtraction. There are
several causes for a
change in absorbance. For example, the reactants become transformed into
reaction
products that absorb in different regions of the spectrum, resulting in
negative and positive
bands; or the frequency might be shifted due to changes in the environment of
the vibrating
bond, resulting in a negative band and a positive band in close proximity
(KumAR, 2014).
[000153] In all cases in Figure 31, the spectra have been corrected by
subtracting the
control sample (HSP exposed to DI water only) thus leaving only the difference
spectra
(i.e. the peaks that have been affected by PFOS sorption). Figure 31 clearly
shows a
number of peaks (-3200, 2900, and 1750-900 cm-1) that increase with increasing
PFOS
concentration. Three peaks can be seen to show a negative absorbance (-3000,
1743 and
1050 cm-1) with the peak at 1743 cm-1 representative of a band associated with
carbonyl
(C=0) stretching vibration (SERVICE et al., 2010). This band is characteristic
of amino
acids, and the fact that it appears increasingly negative with increasing PFOS
concentration, indicates the association of PFOS molecules with this
particular site on the
protein. The spectra and subsequent interpretation is very complicated and
further work on
these is required before any definitive conclusions can be made as to the
PFAS/HSP
interactions. It is clear, however, that there is a definitive association
occurring.
[000154] Figure 32 shows the FTIR spectra of the HSP control and HSP
exposed to
PFOS after thermal destruction. It can be seen that there are remaining large
peaks at
¨1070-1100 cm-1, characteristic of the Si-0 stretching vibration, and
consequently the
FTIR spectral databases used here indicate that the final material after
thermal destruction
is an amorphous silica product. This indicates that all PFAS has been
destroyed during the
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pyrolysis, however this would need to be confirmed with XRD/XRF and or X-ray
Photoelectron spectroscopy analysis.
[000155] TGA-DSC and evolved gas FTIR techniques may additionally be used
to
elucidate the potential sorption mechanisms of the reactions. For example,
Figure 33
shows the evolved gas analysis during the thermal destruction (at 10 C/min)
under an
oxygen atmosphere for hemp protein powder (Figure 33). The region below 2000
cm-1-
wavenumbers is distinctly different for the PFOA exposed sample, and shows the
presence
of carboxylic acid functional groups as well as carbon-fluorine groups below
500 C (<50
min). Large peaks at ¨2400 cm-1 are due to evolved CO2 associated with plant
material
pyrolysis. No adverse gas products have been identified.
[000156] The FTIR spectra of biological systems are very complex, since
they often
consist of overlapping absorption bands from the main components. Therefore,
to extract
the significant (non-redundant) information in the spectra, it is necessary to
apply various
multivariate analysis techniques. This is even more crucial when time
dependent data, such
as that obtained in evolved gas analysis, is used. The data obtained from hemp
protein
powder exposed to various PFAS solutions is complex, however when coupled with
the
analysis of the evolved gases during thermal destruction, the amount of
information which
requires processing is immense.
EXAMPLE 10
[000157] A laboratory bench scale PFAS treatment system has been designed
based on
the results from PFAS removal experiments outlined. A small scale rotary drum
vacuum
(RDV; Figure 34) was applied to the treated waste stream and served two
functions:
(i) to remove the used/spent HSP material. The vacuum component of the
system also serves to dry the spent HSP, eliminating the need for large areas
of land
normally required for dewatering prior to thermal destruction; and
(ii) to "polish" and clarify the treated water, removing any residual
solids from
the remediation stages.
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[000158] The RDV in its current form has been tested using HSP in de-
ionized water at
a solid-to-solution ratio of 100 g/L. The procedure uses a solution of
diatomaceous earth
(DE) to create a filtration cake on the drum prior to removing the HSP waste.
The DE
effectively becomes a highly permeable layer which traps the HSP on the
surface, but
allows the treated water to pass through into the drum. The polished
(decontaminated and
visually clean) water is then removed via the vacuum.
[000159] The treatment stages for PFAS removal using HSP (prior to the RDV
step)
could include any number of methods, including existing batch reactor vessels
such as
those available from Coates hire. Theoretically, any of the current in-line
filtration
treatment plants may be able to be utilized simply by swapping existing
sorbents with the
correct HSP dosing. However, in-line filtration experiments would need to be
trialed first
to determine bed-volume treatment life, pressure changes etc.
[000160] Also of benefit is the utilisation potential of the technology to
current
stockpiles of concentrated PFAS waste, a residual of the GAC/reverse osmosis
PFAS
treatment plants. As salinity does not appear to adversely impact PFAS removal
by HSP,
its application to these waste-streams may be a viable option for this growing
problem in
PFAS remediation.
[000161] Given the rapid kinetics of the reaction, it is proposed that
large "tea bag"
type hemp filters be constructed and placed via a crane into Lake Cochran,
Williamtown,
one of the most PFAS contaminated areas at the RAAF base. Once saturated,
these could
be lifted out to free drain, and the contents analysed, de-watered and
thermally destroyed.
EXAMPLE 11
[000162] PFAS Removal using other plant proteins was measured. The aim was
to
determine the effectiveness of other plant proteins on the removal of PFAS
compounds
from groundwater sourced from MW187s at Williamtown. As each plant protein has
a
different total amount (%) of proteins the laboratory data must be normalised
to compare
final removal figures. Table 17 shows the amino acid and total protein
percentage of each
plant protein powder used. Note: these values are taken from the information
given by the
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manufacturer. Actual protein and amino acid content will be determined by the
National
Measurement Institute (NMI) Laboratories, Melbourne.
Table 17. Plant proteins used to treat PFAS contamination. Protein content (%)
and amino acid content. Note: these
values are taken from the information given by the manufacturer. Actual
protein and amino acid content will be
determined by the National Measurement Institute (NMI) Laboratories,
Melbourne.
Hemp Soy Pea Protein Egg white
Whey Lupin Flour
protein Isolate powder protein
powder (albumin) isolate
Protein (%) 49.9 90.5 80.0 79.0 91.4 38.5
Amino 414k{ffit Oflpotowito
Isoleucine 1,730 4,300 2,500 4,340 6,300 4,400
Leucine 2,840 7,800 4,800 6,820 14,300 7,500
Lysine 1,540 6,500 8,300 6,500 11,200 4,700
Methionine 760 1,400 7,300 3,020 2,400 700
Phenylalanine 1,980 5,400 1,000 4,730 3,800 3,700
Threonine 1,430 3,600 5,100 3,640 5,300 3,400
Tryptophan 480 1,000 5,000 1,320 2,400 800
Valine 2,060 4,500 3,800 5,580 5,600 3,500
Histidine 1,180 2,700 1,890 2,000 2,700
Alanine 1,600 4,200 4,200 4,960 5,700
Arginine 5,430 8,000 8,700 4,650 3,000
Aspartic acid 4,130 12,100 11,500 8,220 12,500
Cysteine/cystine 700 1,400 1,100 2,170 4,000 1,800
Glutamic acid 7,360 20,400 17,200 10,540 17,600
Glycine 1,160 4,200 4,200 2,790 1,800
Proline 1,640 5,300 5,300 3,100 4,500
Serine 2,050 5,700 4,500 5,500 4,500
Tyrosine 1,290 4,100 4,000 3,180 4,200 3,400
[000163]
Figure 35 shows the %PFAS removal for each protein powder prior to
normalization. As can be seen, soy and pea protein powders appear to compare
favourably
to Hemp for removal of PFHxS+PFOS. However, as demonstrated above, using the
Kd
value is an excellent way to compare at a glance the removal efficiencies of
each plant
protein. Figure 36 shows the Kd values for each plant protein which have been
normalized
for total protein content (for ease of viewing both the linear (Figure 36A)
and logarithmic
(Figure 36B) plots are displayed).
CA 03074178 2020-02-27
WO 2019/040979 PCT/AU2018/050916
- 40 -
[000164] It is clear that after normalisation for protein content, hemp
powder is
superior for the removal of both PFHxS+PFOS as well as total sum PFAS with the
overall
removal order being Hemp>Soy>Lupin>Whey>Pea>Egg.
